In a sample of 5.3x10^7 phi-decays observed with the KLOE detector at the Frascati phi-factory Dafne we find 605 eta pi0 gamma events with eta --> gamma\gamma and 197 eta pi0 gamma events with eta --> pi+ pi- pi0. The decay phi --> eta pi0 gamma is dominated by the process phi --> a0 gamma. From a fit to the eta pi0 mass spectrum we find BR(phi --> ao(980) gamma)= (7.4 +- 0.7)x10^-5.
@article{arxiv.hep-ex/0204012,
title = {Study of the Decay phi --> eta pi0 gamma with the KLOE detector},
author = {The KLOE Collaboration},
journal= {arXiv preprint arXiv:hep-ex/0204012},
year = {2012}
}